Recent investigations into the neurochemistry of conduct disorder and antisocial behavior have suggested that activity levels of monoamine oxidase (MAO) and dopamine-beta-hydroxylase (DBH), enzymes involved in the metabolism of serotonergic, dopaminergic and noradrenergic neurotransmitter systems, may differ in antisocial versus non antisocial children. This research will be the initial stage of a longitudinal study to determine the interaction of biological, parental/environmental & intervention variables in predicting antisocial behav.